Impact of human mesenchymal stromal cells on antifungal host response against .

Mesenchymal stromal cells (MSCs) are increasingly given as immunotherapy to hematopoietic stem cell transplant (HSCT) recipients with refractory graft-versus-host disease (GvHD). Whereas the immunosuppressive properties of MSCs seem to be beneficial in GvHD, there is, at the same time, major concern that MSCs increase the risk for infection. We therefore investigated the interplay of human MSCs with and the impact of MSCs on different arms of the anti- host response . Although hyphae increase mRNA levels of in MSCs, the extracellular availability of IL-6 and other pro-inflammatory cytokines remains unaffected. Human MSCs are able to phagocyte conidia, but phagocytosis of conidia is not associated with an alteration of the cytokine production by MSCs. In addition, human MSCs do not affect activation and function of specific CD4 T cells, and MSCs do not negatively impact the oxidative burst activity of phagocytes. Our data indicate that administration of human MSCs is not associated with a negative impact on the host response against and that the fungus does not stimulate MSCs to increase the release of those cytokines which play a central role in the pathophysiology of GvHD.